(Korean name: Hal-la-ma-di-tok-to-ki)
Figs 1–8
Type material. Holotype: female on slide, Bangaeoreum, Mt. Hallasan, Donghong-dong, Seogwipo-si, Jeju Island, South Korea, 33°21′20.55′′ N, 126°31′40.14′′ E, alt. 1660 m, 26.iv.2017, leg. Lee, L.W., Lee, S.M. Paratypes: three female specimens on slides, two specimens used for DNA extraction, 15 specimens in 95% ethanol, same data as holotype; three females on slides, two specimens used for DNA extraction, 20 specimens in 95% ethanol, same site and collectors but different date as type material.
Other material. 24.v.2017; three specimens on slides, two specimens used for DNA extraction, 17 specimens in 95% ethanol, Yeongsil, Mt. Hallasan, Gusanbong-ro, Seogwipo-si, Jeju Island, South Korea, 33°21′30.56′′ N, 126°30′14.51′′ E, alt. 1650 m, 24.v.2017, leg. Lee, L.W., Lee, S.M.; three specimens on slides, two specimens examined for molecular research, 13 specimens in 95% ethyl alcohol, Witsebulgeunoreum, Mt. Hallasan, Seohodong, Seogwipo-si, Jeju Island, South Korea, 33°21′33.64′′ N, 126°31′25.11′′ E, alt. 1700 m, 24.v.2017, leg. Lee, L.W., Lee, S.M.; three specimens on slides, two specimens examined for molecular research, 10 specimens in 95% ethyl alcohol, Utseoreum, Mt. Hallasan, Seoho-dong, Seogwipo-si, Jeju Island, South Korea, 33°21′43.01′′ N, 126°31′23.95′′ E, alt. 1700 m, 24.v.2017, leg. Lee, L.W., Lee, S.M.; three specimens on slides, two specimens examined for molecular research, 12 specimens in 95% ethyl alcohol, Nambyeok, Mt. Hallasan, Sanghyo-dong, Seogwipo-si, Jeju Island, South Korea, 33°21′14.65′′ N, 126°31′59.79′′ E, alt. 1550 m, 24.v.2017, leg. Lee, L.W., Lee, S.M.
Material deposition. All types except five paratypes and voucher specimens are deposited in the National Institute of Biological Resources (NIBR), Incheon, Republic of Korea, and in the Insect Collection, Department of Biology Education, Jeonbuk National University, Jeonju, Korea (ICJU). Five paratypes were sent to Dr. Mikhail Potapov (Moscow State Pedagogical University, Moscow).
Ecology. A. hallaensis sp. nov. was collected from a clump of withered conifer leaves of Korean fir at several sites on Mt. Hallasan, all specimens were found at elevation of 1,500 –1,700 m, firstly found in the Bangaeoreum area (southwest of Mt. Hallasan) in April 2017. Later, it was discovered during further investigations in Youngsil and Whitseoreum (west of Mt. Hallasan), Nambyeok (south of Mt. Hallasan), and Jindalraebat (east of Mt. Hallasan) in May 2017. It was not observed after June of the same year.
Diagnosis. Body length 1.5 to 2.0 mm, color blackish blue. Head with 8 + 8 eyes and narrow PAO. Apical bulb of Ant. IV with 1–2 lobes. Labrum with three prelabral and 4 + 4 postlabral chaetae. Tita with 2, 3, 3 dorsal and 1, 1, 0 ventral tenent hairs. Emp length less than 2/7 of claw.
Description. Body color blackish blue (Fig. 1a). Body size 1.5–2.0 mm (n=13).
Head (Figs 2–5, Fig 8c). Head with 8 + 8 eyes. PAO narrow (Fig. 3), 2 or 3 times longer than narrowest width. Apical bulb of Ant. IV with 1–2 lobes and some blunt sensilla. Ant. III with 2 external, 2 internal, and 2 lateral sensilla in sensory organ, additional sensilla absent; 1 microsensillum on same side as sensory organ. Ant. II with 1 ventro-lateral sensillum and 1 dorsal, 1 lateral, and 1 ventro-lateral microsensillum. Ant. I with 2 sensilla on ventral side, and 1 ventral and 1 dorsal microsensillum (Fig. 2). Labrum with 5, 5, 4 labral and 3 prelabral chaetae (Fig. 5); 4 + 4 postlabial chaetae (Fig. 8c). Maxillary outer lobe with simple palp, and only 1 sublobal hair and basal chaeta (Fig. 5; Fjellberg 1984). Maxillary head shape as in A. laricis (Fjellberg 2007). Labial palp also as in A. laricis, with 5 papillae (A–E); papilla A with 1 guard chaeta (a 1 present), papilla B with 3 guard chaetae (b 1 –b 3 present, b 4 absent), papilla C without guard chaetae, papilla D with 3 guard chaetae (d 1 –d 3 present, d 4 absent), and papilla E with 4 guard chaetae (e 1, e 2, e 3, e 6 present, e 4, e 5, and e 7 absent), and papilla H with 2 guard chaetae (Fig. 4; Fjellberg 1999). Labium with 3 proximal chaetae. Basomedial field with 4 smooth chaetae; basolateral field always with 5 chaetae (Fjellberg 1999).
Legs (Figs 6a–c). Claw normal in shape, without teeth. Unguis almost 8 times longer in inner length than unguiculus. Tita with blunt tenent hairs, 2 on dorsal and 1 on ventral side of front leg; 3 on dorsal and 1 on ventral side of middle leg; and 3 on dorsal side of hind leg, tenent hair on ventral side of hind leg absent (Figs 6a–c).
Ventral tube (Fig. 7). Ventral tube with 3 + 3 laterodistal and 2 + 2 posterior chaetae.
Body chaetotaxy (Figs 8a–c). Chaetae on dorso-medial line of Th. II – Abd. V: 6–7, 4/3–4, 3–5, 4–5, 5–6, 3–5 on each side (Fig. 8b). Macrochaetae on dorsal side of Th. II – Abd. V: 1, 1/0, 0, 0, 2, 4 on each side (Fig. 8b). Sensilla formula of Th. II – Abd. V: 2, 2/1, 1, 1, 1, 4 on each side (Fig. 8a). Microsensilla formula of Th. II – Abd. V: 0, 0/1, 0, 0, 0, 0 on each side (Fig. 8a). Ventro-medial chaetae of Th. I – Th. III as 0, 0, 3–6 on each side (Fig. 8c). Tenacular area with 6–11 ordinary chaetae. Furcal subcoxa area with 19–24 ordinary chaetae.
Distribution. Jeju Island, South Korea.
Remarks. This species showed the identical pattern of macrochaetae and sensilla on Th. II – Abd. IV with A. laricis and A. palearcticus (Figs 8a–b). However, the new species differs from A. laricis and A. palearcticus in the number of knobbed hairs on ventral side of legs (1, 1, 0 in A. hallaensis sp. nov. vs. 2, 2, 1 in A. laricis and A. palearcticus). The new species can also be distinguished from A. laricis by the number of sensilla on Ant. III (without additional sensilla in A. hallaensis sp. nov. and A. palearcticus vs. with 4–7 additional sensilla in A. laricis) (Table 5).
Etymology. The species was named after Mt. Hallasan, where it was collected.